Rather than describe a hypothetical future Saint Louis, I made a map of a Saint Louis made up of Saint Louis City and County, posted here:
I made the map using Geographic Information System software, ArcMap. My goal was to optimize for equal population, and then to see how other demographics worked out based on that benchmark. This map is intended only as a proof of concept, because there are a number of problems with it.
First, cities are split between districts, sometimes right down the middle. Second, this map doesn't take into account geography, and I'm not sure what sort of spatial problems would arise i.e. hills, rivers, parks, roads, etc. Depending on who is asked, there may be other problems or the things mentioned may not be problems. One thing that revealed itself during this analysis is that is just doesn't seem possible to equalize demographic factors across districts - it is possible to optimize for population, but it will be done at the expense of other demographic factors.
Much like the region as it is, this map entails spatial segregation. Social problems aren't solved entirely by redrawing administrative boundaries, though it seems more likely that a number of other problems can be, like fragmented and inefficient government. A quick explanation on the second picture, the data table. I did fairly well optimizing for population and keeping districts contiguous.
The region is largely white-black; my intent was not to marginalize other racial or ethnic populations by excluding them from analysis, but rather to keep this map simple as a matter of prudence. Median Household Income figures are the sums of the median household income of the underlying census blocks that make up the districts. People in poverty is in real terms, and again couldn't be optimized. Combined Median Household Value is similar to Median Household Income - that figure is the sum of the Median Household Values of each of the underlying census blocks in the district. Finally, Unemployed Persons are in real numbers.